1. Field of the Invention
The present invention relates to a seat belt retractor used in a motor vehicle, and more particularly to a retractor of the type in which at least the belt retracting work is effected by an electric motor mounted to the retractor.
2. Description of the Prior Art
Nowadays, there has been proposed a so-called "electrically actuated seat belt retractor" for simplifying the belt handling work imposed to a belt user, in which at least the belt retracting work is effected by an electric motor in response to an instruction signal issued from a control unit. One of the retractors of this type is disclosed in secondarily laid-open Japanese Patent Application Specification No. 52-9891.
However, this type retractor has suffered from the drawback that as the belt retracting work (and/or the belt feeding work) is achieved by the electric motor per se, and upon failure of the electric circuit for the motor, the motor fails to effect the belt retracting work (and/or the belt feeding work). Thus, in such a trouble case, the belt user has to bear the obstructive unretracted seat belt all the time during his or her drive.